There are two columns datetimerange[] type.
How to write the following query in sqlalchemy?
SQL:
unnest(range_array_1) && unnest(range_array_2)
I tried this method, but it gives an error
session.query(table_1.id).filter(func.unnest(table_1.range_array_1).overlaps(func.unnest(table_2.range_array_2 )))
AttributeError: Neither 'Function' object nor 'Comparator' object has an attribute 'overlaps'
Related
I have a table that has a column video_ids, it is of a bigint[] type. I would like to find all the rows that have any of the elements from the array passed in a select statement. So, if I have a row that has a video_ids field that looks like this:
{9529387, 9548200, 9579636}
I would like to fetch it if I pass an array that has any of this video_ids. I thought I would do that with any, but I am not sure how to do this in SQL, I have tried with this:
select id, finished, failed, video_ids, invoiced_video_ids, failed_video_ids
from video_order_execution
where order_ids = any(
'{9548200, 11934626, 9579636, 11936321, 11509698, 11552728, 11592106, 11643565, 11707543, 11810386, 11846268}'
::bigint[]);
I get an error if I do that:
ERROR: operator does not exist: bigint[] = bigint Hint: No operator
matches the given name and argument types. You might need to add
explicit type casts.
How can I make such a statement that would do the job for what I need?
Use the operator && which returns true if the 2 operands have any common items:
select id, finished, failed, video_ids, invoiced_video_ids, failed_video_ids
from video_order_execution
where order_ids &&
'{9548200, 11934626, 9579636, 11936321, 11509698, 11552728, 11592106, 11643565, 11707543, 11810386, 11846268}'::bigint[];
I need to find out the schema of a given JSON file, I see sql has schema_of_json function
and something like this works flawlessly
> SELECT schema_of_json('[{"col":0}]');
ARRAY<STRUCT<`col`: BIGINT>>
But if I query for my table name, it gives me the following error
>SELECT schema_of_json(Transaction) as json_data from table_name;
Error in SQL statement: AnalysisException: cannot resolve 'schemaofjson(`Transaction`)' due to data type mismatch: The input json should be a string literal and not null; however, got `Transaction`.; line 1 pos 7;
The Transaction is one of the columns in my table and after checking it manually I can attest that it is of String type(json).
The SQL statement has it to give me the schema of the JSON, how to do it?
after looking further into the documentation that it is clear that the word foldable means that of the static one, and a column from a table JSON won't work
for minimal reroducible example here you go:
SELECT schema_of_json(CAST('{ "a": "b" }' AS STRING))
As soon as the cast is introduced in the above statement, the schema_of_json will fail......... It needs a static JSON as it's input
I want to get the latest date from my database.
Here is my sql statement.
select "RegDate"
from "Dev"
where "RegDate" = (
select max("RegDate") from "Dev")
It works in my database.
But how can I use it in django?
I tried these codes but it return error. These code are in views.py.
Version 1:
lastest_date = Dev.objects.filter(reg_date=max(reg_date))
Error:
'NoneType' object is not iterable
Version 2:
last_activation_date = Dev.objects.filter(regdate='reg_date').order_by('-regdate')[0]
Error:
"'reg_date' value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format."
I've defined reg_date at beginning of the class.
What should I do for this?
You make things too complicated, you simply order by regdate, that's all:
last_activation_dev = Dev.objects.order_by('-regdate').first()
The .first() will return such Dev object if it is available, or None if there are no Dev objects.
If you only are interested in the regdate column itself, you can use .values_list(..):
last_activation_date = Dev.objects.order_by('-regdate').values_list('regdate', flat=True).first()
By using .filter() you actually were filtering the Dev table by Dev records such that the regdate column had as value 'reg_date', since 'reg_date' is not a valid datetime format, this thus produced an error.
In slick 3 with postgres, I'm trying to use a plain sql query with a tuple column return type. My query is something like this:
sql"""
select (column1, column2) as tup from table group by tup;
""".as[((Int, String))]
But at compile time I get the following error:
could not find implicit value for parameter rconv: slick.jdbc.GetResult[((Int, String), String)]
How can I return a tuple column type with a plain sql query?
GetResult[T] is a wrapper for function PositionedResult => T and expects an implicit val with PositionedResult methods such as nextInt, nextString to extract positional typed fields. The following implicit val should address your need:
implicit val getTableResult = GetResult(r => (r.nextInt, r.nextString))
More details can be found in this Slick doc.
I want to query data from mongo and filter them to many stacks
The logic is like:
objs = collection.find({"name":"BOB"})
t_list = ["Math","History"]
for t in t_list :
subjects = objs.find({{"subjects":t}})
# do_somethig(subjects)
But pymongo will raise error AttributeError: 'Cursor' object has no attribute 'find'
I want to know can pymongo do this ?? ( query one time and then filter the data I want??)